It is important to estimate power consumption at each stage of a microprocessor design to ensure that the power consumption remains within a specified budget. The power estimation is done by simulation based tools such as a dynamic cycle-by-cycle (i.e., vector-based) simulation. However, the power estimation done by the simulation based tools results in very long run-times, especially for large circuits. In earlier stages of the microprocessor design, a faster turn-around time for power estimation is more important, even at the expense of some accuracy. Thus, long run-times due to the simulation based tools are unacceptable in earlier stages of the microprocessor design.